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/* SPDX-License-Identifier: GPL-2.0 OR MIT */
#ifndef __DRM_EXEC_H__
#define __DRM_EXEC_H__
#include <linux/compiler.h>
#include <linux/ww_mutex.h>
#define DRM_EXEC_INTERRUPTIBLE_WAIT BIT(0)
#define DRM_EXEC_IGNORE_DUPLICATES BIT(1)
/*
* Dummy value used to initially enter the retry loop.
* internal use only.
*/
#define DRM_EXEC_DUMMY ((void *)~0)
struct drm_gem_object;
/**
* struct drm_exec - Execution context
*/
struct drm_exec {
/**
* @flags: Flags to control locking behavior
*/
u32 flags;
/**
* @ticket: WW ticket used for acquiring locks
*/
struct ww_acquire_ctx ticket;
/**
* @num_objects: number of objects locked
*/
unsigned int num_objects;
/**
* @max_objects: maximum objects in array
*/
unsigned int max_objects;
/**
* @objects: array of the locked objects
*/
struct drm_gem_object **objects;
/**
* @contended: contended GEM object we backed off for
*/
struct drm_gem_object *contended;
/**
* @prelocked: already locked GEM object due to contention
*/
struct drm_gem_object *prelocked;
};
/**
* drm_exec_obj() - Return the object for a give drm_exec index
* @exec: Pointer to the drm_exec context
* @index: The index.
*
* Return: Pointer to the locked object corresponding to @index if
* index is within the number of locked objects. NULL otherwise.
*/
static inline struct drm_gem_object *
drm_exec_obj(struct drm_exec *exec, unsigned long index)
{
return index < exec->num_objects ? exec->objects[index] : NULL;
}
/* Helper for drm_exec_for_each_locked_object(). Internal use only. */
#define __drm_exec_for_each_locked_object(exec, obj, __index) \
for (unsigned long __index = 0; ((obj) = drm_exec_obj(exec, __index)); ++__index)
/**
* drm_exec_for_each_locked_object - iterate over all the locked objects
* @exec: drm_exec object
* @obj: the current GEM object
*
* Iterate over all the locked GEM objects inside the drm_exec object.
*/
#define drm_exec_for_each_locked_object(exec, obj) \
__drm_exec_for_each_locked_object(exec, obj, __UNIQUE_ID(drm_exec))
/* Helper for drm_exec_for_each_locked_object_reverse(). Internal use only. */
#define __drm_exec_for_each_locked_object_reverse(exec, obj, __index) \
for (unsigned long __index = (exec)->num_objects - 1; \
((obj) = drm_exec_obj(exec, __index)); --__index)
/**
* drm_exec_for_each_locked_object_reverse - iterate over all the locked
* objects in reverse locking order
* @exec: drm_exec object
* @obj: the current GEM object
*
* Iterate over all the locked GEM objects inside the drm_exec object in
* reverse locking order. Note that the internal index may wrap around,
* but that will be caught by drm_exec_obj(), returning a NULL object.
*/
#define drm_exec_for_each_locked_object_reverse(exec, obj) \
__drm_exec_for_each_locked_object_reverse(exec, obj, __UNIQUE_ID(drm_exec))
/*
* Helper to drm_exec_until_all_locked(). Don't use directly.
*
* Since labels can't be defined local to the loop's body we use a jump pointer
* to make sure that the retry is only used from within the loop's body.
*/
#define __drm_exec_until_all_locked(exec, _label) \
_label: \
for (void *const __maybe_unused __drm_exec_retry_ptr = &&_label; \
drm_exec_cleanup(exec);)
/**
* drm_exec_until_all_locked - loop until all GEM objects are locked
* @exec: drm_exec object
*
* Core functionality of the drm_exec object. Loops until all GEM objects are
* locked and no more contention exists. At the beginning of the loop it is
* guaranteed that no GEM object is locked.
*/
#define drm_exec_until_all_locked(exec) \
__drm_exec_until_all_locked(exec, __UNIQUE_ID(drm_exec))
/**
* drm_exec_retry_on_contention - restart the loop to grap all locks
* @exec: drm_exec object
*
* Control flow helper to continue when a contention was detected and we need to
* clean up and re-start the loop to prepare all GEM objects.
*/
#define drm_exec_retry_on_contention(exec) \
do { \
if (unlikely(drm_exec_is_contended(exec))) \
goto *__drm_exec_retry_ptr; \
} while (0)
/**
* drm_exec_is_contended - check for contention
* @exec: drm_exec object
*
* Returns true if the drm_exec object has run into some contention while
* locking a GEM object and needs to clean up.
*/
static inline bool drm_exec_is_contended(struct drm_exec *exec)
{
return !!exec->contended;
}
/**
* drm_exec_retry() - Unconditionally restart the loop to grab all locks.
* @exec: drm_exec object
*
* Unconditionally retry the loop to lock all objects. For consistency,
* the exec object needs to be newly initialized.
*/
#define drm_exec_retry(_exec) \
do { \
WARN_ON((_exec)->contended != DRM_EXEC_DUMMY); \
goto *__drm_exec_retry_ptr; \
} while (0)
/**
* drm_exec_ticket - return the ww_acquire_ctx for this exec context
* @exec: drm_exec object
*
* Return: Pointer to the ww_acquire_ctx embedded in @exec.
*/
static inline struct ww_acquire_ctx *drm_exec_ticket(struct drm_exec *exec)
{
return &exec->ticket;
}
void drm_exec_init(struct drm_exec *exec, u32 flags, unsigned nr);
void drm_exec_fini(struct drm_exec *exec);
bool drm_exec_cleanup(struct drm_exec *exec);
int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj);
void drm_exec_unlock_obj(struct drm_exec *exec, struct drm_gem_object *obj);
int drm_exec_prepare_obj(struct drm_exec *exec, struct drm_gem_object *obj,
unsigned int num_fences);
int drm_exec_prepare_array(struct drm_exec *exec,
struct drm_gem_object **objects,
unsigned int num_objects,
unsigned int num_fences);
#endif
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